Image signal processors (ISP) may be used for image processing in digital cameras, mobile phones, and other devices. ISPs typically process images on a per-frame or a per-line basis. For high resolution images, this may lead to high clock requirements and high power consumption.
In some cases, when a user wants to take a photograph, they may launch the camera and at some point of time, and click the shutter button to capture the intended scene. During the time between the user positioning the camera and actually capturing an image, numerous similar frames are being processed by the ISP, causing unnecessary power consumption.